Beginning on 20 August 2011, Bill McKibben is leading what may be the largest green civil disobedience campaign in a generation, against the proposed construction of the 1,600-mile long Keystone XL pipeline. The pipeline would transport oil from the Alberta tar sands in Canada to American refineries at the Gulf of Mexico, and many are concerned about the associated impacts on the climate. Digging up new sources of fossil fuels will inevitably increase the amount of CO2 in the atmosphere, and the tar sands result in higher carbon emissions than even conventional oil. On 15 June 2011, the Energy and Power Subcommittee of the House Energy and Commerce Panel approved a bill to expedite a decision on the pipeline, possibly trying to rush it through before adequate environmental impact assessments are completed.

Background and Politics

Tar sands (a.k.a. oil sands) are an unconventional deposits of petroleum containing bitumen, which is a very viscous form of petroleum generally known as tar or very heavy crude oil. Alberta, Canada contains the largest deposits of crude bitumen in the world, the biggest of which is the Athabasca tar sands.

There is political pressure in the USA to utilize oil from the tar sands, because although it’s not quite a domestic energy source, obtaining oil from our friendly neighbors to the north is considered preferable to relying on sources in the less politically stable and friendly Middle East.

Environmental Impacts

Before we examine the climate impacts of the tar sands, it’s worth noting that they result in substantial adverse impacts to the environment in general, as is clear in aerial photographs from Google of the region (Figure 1).

Figure 1: 2011 Google aerial photograph of the Athabasca tar sands. The photograph is approximately 30 miles across. The most clearly visually impacted area is approximately 15 miles across.

“Canada’s or Alberta’s guidelines for the protection of aquatic life were exceeded for seven [priority pollutants]—cadmium, copper, lead, mercury, nickel, silver, and zinc—in melted snow and/or water collected near or downstream of development.”

Additionally, there are always concerns about environmental impacts related to potential oil spills and leaks. On a similar pipeline, Keystone I, there were 12 spills over a period of less than a year, and a team of University of Nebraska hydrologists expressed concern over the associated risks to drinking and irrigation water supplies in the US Midwest, though which the pipeline would run.

Greenhouse Gas Emissions

Making liquid fuels from bitumen requires energy for steam injection and refining. Currently the energy is produced from natural gas. This process generates more greenhouse gas emissions per barrel of final product than the production of conventional oil.

There is a slight challenge in quantifying the climate impact of tar sands oil as compared to conventional oil, because there are different ways to make this comparison. Approximately 80% of the carbon from any barrel of crude is emitted when it’s burned. Therefore, evaluating well-to-wheel (extraction to combustion) emissions, tar sands emit approximately 10 to 45% more greenhouse gases than combustion of conventional oil. However, if we exclude combustion and evaluate well-to-tank emissions, tar sands emissions are approximately twice those of conventional oil. According to a recent US Environmental Protection Agency (EPA) assessment, tar sands well-to-tank emissions are approximately 82% higher than conventional oil.

Keystone Pipeline Emissions

The EPA also evaluated the greenhouse gas emissions specifically associated with the proposed Keystone pipeline which McKibben’s group is protesting.

“recognizing the proposed Project ‘s lifetime is expected to be at least fifty years, we believe it is important to be clear that under at least one scenario, the extra GHG emissions associated with this proposed Project may range from 600 million to 1.15 billion tons CO2-e, assuming the lifecycle analysis holds over time”

Over 1 billion tons of equivalent CO2 emissions is a substantial chunk of emissions. We recently discussed The Critical Decade report produced by the Climate Commission established by the Australian government. Their report concluded that humanity can emit not more than 1 trillion tonnes of CO2 between 2000 and 2050 to have a probability of about 75% of limiting temperature rise to 2°C or less. According to the latest data, between 2000 and 2010 we emitted approximately 300 billion tons of CO2, so after 20% of the allotted timeframe, we’re already over 30% of the way through the allotted emissions.

Climate Concerns

In addition to being more emissions-intensive than conventional oil, the main concern is that exploiting the tar sands is conceptually backwards. As The Critical Decade report made clear, we need to be looking for ways to leave fossil fuels in the ground, not trying to find more unconventional sources of carbon for combustion. The USA in particular has taken very few concrete steps to minimize its greenhouse gas emissions to this point. Building the Keystone pipeline to exploit an unconventional source of fossil fuels is a step in the wrong direction, and will encourage other countries to follow suit. If we’re to have any hope of achieving sufficient global greenhouse gas emissions cuts, the USA needs to start leading the way in finding ways to reduce fossil fuel consumption, not lead the way in finding ways to burn new unconventional sources, especially when they’re more emissions-intensive than conventional sources.

Zach is the director of CleanTechnica, the most popular cleantech-focused website in the world, and Planetsave, a world-leading green and science news site. He has been covering green news of various sorts since 2008, and he has been especially focused on solar energy, electric vehicles, and wind energy since 2009.
Aside from his work on CleanTechnica and Planetsave, he's the founder and director of Solar Love, EV Obsession, and Bikocity.
To connect with Zach on some of your favorite social networks, go to ZacharyShahan.com and click on the relevant buttons.

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